HTML-EXTERNAL STYLING: We have already discussed about Styling in HTML in pervious chapters,in this chapter we are going
to discuss how to apply styles for HTML document or webpage using external sheet.it means if you have more pages in your
site, at that time it helps you a lot.if you apply style in External Style Sheet it will automatically applicable to all pages
which having link to external style sheet using div or class attribute.other wise you need to apply CSS for each div or class for
each page indivisually.to link external style sheet to your document just add peice of code in head section for each document.below
i will explain in detail with example & also watch video for better understanding.